CVE-2025-9560 is a stored cross-site scripting (XSS) vulnerability identified in the Colibri Page Builder plugin for WordPress, a popular website building tool. The vulnerability arises from improper neutralization of user-supplied input within the plugin's colibri_newsletter shortcode, where insufficient input sanitization and output escaping allow authenticated users with contributor-level access or higher to inject arbitrary JavaScript code into pages. When other users access these compromised pages, the injected scripts execute in their browsers, potentially enabling attackers to hijack user sessions, steal cookies, perform actions on behalf of users, or deface the website. The vulnerability affects all plugin versions up to and including 1.0.334. The CVSS v3.1 base score is 6.4, reflecting medium severity, with an attack vector of network, low attack complexity, requiring privileges (contributor or above), no user interaction, and a scope change indicating that the vulnerability affects resources beyond the initially compromised component. The impact primarily affects confidentiality and integrity, with no direct availability impact. No known exploits have been reported in the wild yet. The vulnerability was publicly disclosed on October 11, 2025, and no official patches have been linked yet. The CWE classification is CWE-79, which corresponds to improper neutralization of input during web page generation, a common cause of XSS vulnerabilities. Given WordPress’s widespread use in Europe, this vulnerability poses a significant risk to websites using the Colibri Page Builder plugin, especially those allowing multiple contributors to publish content. Attackers with contributor access can leverage this flaw to compromise site visitors or administrators, potentially leading to broader compromise or reputational damage.

For European organizations, this vulnerability can lead to unauthorized script execution within the context of affected websites, compromising user confidentiality and site integrity. Attackers could steal session cookies, enabling account takeover or privilege escalation. This is particularly critical for organizations relying on WordPress sites for customer interaction, e-commerce, or internal communications. The vulnerability could facilitate phishing, malware distribution, or defacement, damaging brand reputation and customer trust. Since contributor-level access is required, insider threats or compromised contributor accounts increase risk. The lack of availability impact means service disruption is unlikely, but data leakage and unauthorized actions remain significant concerns. Organizations with high traffic or sensitive user data are at greater risk. Additionally, the scope change in the CVSS vector suggests that the vulnerability could affect components beyond the immediate plugin, potentially impacting integrated systems or third-party services. The absence of known exploits in the wild provides a window for proactive mitigation before active attacks emerge.

1. Monitor the vendor’s announcements closely and apply patches immediately once available to remediate the vulnerability. 2. Until patches are released, restrict contributor-level access to trusted users only, minimizing the risk of malicious script injection. 3. Implement strict input validation and output encoding on all user-supplied content, especially in shortcodes or dynamic page elements. 4. Deploy a Web Application Firewall (WAF) with rules specifically targeting XSS payloads to detect and block malicious requests. 5. Conduct regular security audits and code reviews of custom plugins or themes that interact with user input. 6. Educate contributors about secure content practices and the risks of injecting untrusted code. 7. Use Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts on affected websites. 8. Monitor logs and website content for unusual script injections or modifications. 9. Consider isolating or sandboxing user-generated content to limit the impact of potential XSS attacks. 10. Backup website data regularly to enable quick restoration if defacement or compromise occurs.